8 Things You Should Never Put in the Microwave

A scalding glass of water can explode in your face when microwaved, which makes for a very bad time.

We may think we know everything there is to know about microwaves, but we really don’t. It cooks foods fast and hot, and there are dangers lurking around every corner. We’ve rounded eight things that you shouldn’t even think about microwaving.

The microwave oven became a household item in the 1970s, even though they were first put on the market in the 1950s (the earliest microwaves would have cost upwards of $11,000 in today’s dollars). By 1986, about a quarter of all U.S. households had a microwave, and that number is well past 90 percent today. But how exactly does it work?

In a word, radiation. Microwave radiation, to be exact, hence the name. Microwaves generate this electromagnetic radiation and then bombard food with it, speeding up the water and fat molecules and then heating it up via the friction between these molecules as they crash into each other. It’s all very scientific, but at the end of the day it heats food up like nothing else on earth, and is a bit of a technological marvel.

Certain things, like foods that are high in fat and water, react just fine to being bombarded with microwaves, and tend to heat quickly and evenly. But certain other objects, like metal, act like antennas and—as anyone who’s seen American Hustle knows—can ignite into a raging fire almost instantly.